Controller for electric motors



. P 1931- P. B. HARWOOD 1,801,502

CONTROLLERFOR ELECTRIC MOTORS Filed March 28, 1927 5 sheets-sheet 1Master POSiHw n INVENTOR.

3% Jim/wood.

A TTORNEY P. B. HARWOOD April 21:, 1931.

CONTROLLER FOR ELECTRIC MOTORS 3 Sheets-Sheet 2 Filed March 28, 1927 LSl T BE F W m imm gm.

? JL'INVENTOR.

ATTORNEY w A ril 21, 1931. P. B. HARWOOD CONTROLLER FOR ELECTRIC MOTORSFiled March 28, 1927 3 Sheets-Sheet 3 x AU INVENTOR. A5. Jim/wand.

ATTORNEY Patented Apr. 21, 193i 7 UNITED STATES PATENT orrlca PAISLEY B.HABWOOD. OF II'LWAUKEE, WISCONSIN, ASSIGNOB, BY HERE ASSIGN- MEN'IS, TOCUTLER-H 7 O1 DEAWARE B, BIG, KILWAUKEE, WISCONSIN, A COBZPOBATIOHCONTROLLER FOR ELECTRIC MOTORS Application filed larch 28, 1927. SerialNo. 179,093.

' This invention relates to improvements in controllers for electricmotors, and more particularly to control of certain of the operatingmotors of blast furnace charging equipment.

. Blast furnace tops as ordinaril constructed comprise a pair ofcharging be arranged one above the other, and which are so operated asto prevent simultaneous openin of both bells. The chargin uipmentfikewise includes one or more siip uckets adapted to intermittentlydischarge material into the furnace to? at a given point in .the periphery'thereo In such equipment the skip hoist is interlocked with thefurnace top contfiol and the latter is in turn interlocked with t 0 topof'the furnace, so that each part of this equipment must complete agiven cycleof operation beforethe skip hoist can operate again; Thusifthe skip hoist is faster than the rest of the equipment it must bedelayed for the reasons aforementioned. This is almost always'the-casein furnace top control equipment as heretofore constructed; and one.

ob ect of my invention is to provide for reducing the time required foroperation of certain elements'of the equipment whereby the skip hoistmay be operated continuously and more rapidly, thus saving considerabletime throughout the entire furnace charging operation. i Anotherobjectis to provide im roved furnace top control equipment where y the timerequired for completing the furnace charging operation may be materiallydecreased. Another and more specific object is to provide means forexped't' the material dis-- tributing operation where y continuousnormal operation of the other elements of the char ng uipment ispermitted.

O ier 0 jects and advanta will be pointed out or will be apparent in thecourse of the following descri ion.

The accompanying awings illustrate an embodiment of my invention whichwill now be described, it being understood that variouschanges may bemade in the details of convstructions and operation of the controllerwithout departing from the spirit and scope ll hoist which operates thebells at the of my invention as set forth in the appended claims.

In the drawings, Figure 1 illustrates schematically and diagrammaticallya' furnace top controller constructed in accordance l6 with myinvention.

Fig. 2 is an across-the-line diagram of the circuats and connectionsillustrated in Fig. 1, an 7' Fig. 3 is a diagrammatic view of one typeof furnace top in the control of which my invention may be applied.

Referrin first to Fig. 1, the reference character designates generally areversible motor for effecting rotary movement of a distributing ho perassociated with the small bell of the urnace top; said motor havin anarmature a, series field SF, and shunt field SHF. Thus assuming closureof knife switches KS and KS, motor M is adapted to be connected to linesL, L upon closure of main switch M and simultaneous closure of switchesF F, or B B in the manner hereinafter described. Liotor M is connectedthrough suitable gearing to said distributing hopper to effectintermittent partial rotation of the latter in the manner hereinafterdescribed.

Completion and interruption of the energizing circuit of motor M4 issubject to control b the instrumentalities now to be describe As shown anormally open switch SK is adapted to be closed u on dischargingpositioning of one of the s 'p buckets of a two-bucket hoist, whereas anormally open switch SK is likewise adapted to be closed upondischarging positionm of the other skip bucket. Control of sai switchesmay be effected in any suitable or well known manner, as by means of nut5 which is movable by screw 6 connected through any suitable gearing 7with the skip operating cable or the like.

Switches SK and SK in turn control the energizing circuit of theoperating winding MS of a ratcheting device for effecting stepby-stepmovement of a master switch shown at the lower left hand sideof Fi 1,said circuit being additionally subj to control by anelectromagnetically operable 0 sired.

latching device 8, but subject to release upon energization of atripping coil TC. As shown switch LS is provided with normally open maincontacts LS LS and normally closed auxiliary contacts LS LS.

' The ratchetingmechanism MS of the master switch is provided withnormally closed contacts MS and normally open contacts MS. 7 v

The control system further includes a ratcheting device having a windingPS i adapted upon 'energizat-ion to effect step-bystep movement of arotary position switch shown at the lower right hand side of Fig. 1. Arelay TB having contacts TR is adapted under conilitions hereinafterdescribed to complete the energizing circuits of main switch M andswitches F F or B B selectively. Closure of said contacts TB. issubjected to a delay by means of a dashpot TR. FH and BH indicate rotaryswitches of a well knownv type adapted to be connected through suitablegearing with the rotatable distributing hopper; each of said switchesbeing adapted to make one complete revolution upon each rotary movementof the hopper through an angle of 60.

As shown the master switch is provided with sixty equally spacedbuttons, with each alternate one of-which a bridging contactor isadapted to make electrical contact for purposes hereinafter described.In other words the bridgin contactor 55 is adapted to move through t espace of two buttons upon each operation of the master switch ratchetingmechanism. --Hence it is obvious that each of the alternate non-activecontacts of the master switch might be omitted if de- Theposition switchis provided with fortyfive equally spaced active contacts, and thebridging contactor 75 is adapted to be moved through one space upon eachoperation of the ratcheting mechanism PS of the position switch. Thearrangement and functions of the various contact segments on the masterand position switches will be described more fully in connection withFig. 2; it being noted, vhowever, that said switches are preferablyprovided with suitable le ends or specific form shown herein is ada tedto permit reception and discharge 0 five skip bucket loads by bell B andhopper, F without rotation of the latter. After discharge of each of thenext five skip loads into hopper F the latter is rotated-through anangle of 60. prior to opening or lowering of bell B. In alike mannerhopper F is rotated through an angle of 120 prior to discharge of eachof the next five skip loads from small bell B. Upon reception of thenext skip load by hopper F the latter is rotated in a reverse directionthrough an an 1e of 180, and the next four skip loads are andled in alike manner. Thereafter for'thc next five skip loads hopper F is rotatedin said reverse direction through an angle of 120, and thereafter forthe next fi-ve skip loads hopper F is rotated in said reverse directionthrough an angle of 60. As will be obvious the provislon of means foreffecting reverse operation of hopper F will effect a saving of fortyper cent of the time required for the furnace charging operation; whichis a feature of'great importance in this art.

Operation of the device'will now be described with more particularreference to the diagram of Fig. 2. Withthe knife switches KS and KSclosed and with the master switch and the position switch in zeroposition as shown in Fig 2, upon movement of one of the skip buckets Gto the top of the furnace, closure of switch contacts SK iselfected in awell kno n manner. This completes an energizing circuit for the windingMS ofthe master switch ratchetin mechanism, which circuit may be tracedrom line L by conductor 50 through the normally closed contacts MS ofsaid mechanism, conductor 51 "through said winding, conductor 52,normally closed contacts LS of switch LS,

conductor 53, contacts SK and conductor 54 operated to effect movementof bridging contactor 55 through two spaces whereby it engages button 1of the-0 position indicating contacts. The 0 position indicating lamp isthus lighted, the circuit thereof extending from line L by conductor 56through said lamp, conductor 57 to contact segment 58, contactor 55 tosaid button 1, and conductor 59 to line L".

Operation of said ratcheting mechanism also effects opening of contactsMS to effect inclusion of protective resistance r in the energizingcircuit of winding MS. Closure of contacts MS of said mechanism likewisecompletes an energizing circuit for the winding of switch LS, saidcircuit extending from line L by conductors 50 and 60 through saidcontacts MS conductors 61 and 62 to line L The ratcheting mechanism isthus I through said winding LS, conductor 63 I through normally closedauxiliary contacts LS" of said switch, conductors 64 and 53 throughcontacts SK, and conductor 54 to line L'. Switch LS upon closure is heldin closed position by means of latch 8, pendin release of said latch bytrippin coil TC in the manner hereinafter describe it being noted thatthe energizing circuit of winding LS is interrupted immediately throu hopening of contacts LS of said switch. imllarly upon closure of switchLS the energizing circuit of winding MS is interrupted through openingof normally closed auxiliary contacts LS of the former.

Contacts LS and LS of switch LS are likewise closed, and upon movementof the second skip bucket to the furnace top switch contacts SK areclosed, thereby completing an alternative energizing circuit for windingMS; which circuit extends from line L through said winding to conductor52 as heretofore traced, thence through said contacts LS by conductor 65through contacts SK, and conductors 66 and 54 to line L. The

- ratcheting mechanism thus moves bridging contactor 55 through two morespaces to contact button 2 in the 0 section of the master switch. The 0position lamp remains lighted. Upon closure of contacts MS in the manneraforedescribed an energizing circuit is completed for tripping coil TC,said circuit extending from line L by conductors 50 and through saidcontacts, conductors 61 and 67 through said coil TC, conductor 68through contacts LS conductors 69 and through contacts SK, and thence toline L as previously traced. Upon tripping of the latch switch LSassumes its normal position wherein contacts LS LS are opened andcontacts LS, LS closed; so that upon return of the first mentioned skipbucket to the furnace top the operation first described is repeated,which effects movement of bridging contactor 55 into engagementwithbutton 3 in the 0 section of the master switch. Operation of the skipbuckets efiects intermittent operation of the ratcheting mechanism inthe manner aforedescribed until five bucket loads have been dumped intothe furnace top; whereas during such time the motor M has not beenenergized.

owever, upon arrival and dumping of the sixth bucket load into thefurnace top switch SK is closed to efiect completion of the energizingcircuit of winding MS, as will be obvious; whereupon bridging contactor55 is moved two spaces from contact button 5 of the 0 section of themaster switch into engagement with button 1 ofthe 60 section. The

energizing circuit of the 0 position lamp-is thus interrupted; whereasan'ener gizing circuit for the operatin winding of timing re lay TB iscomplete Said circuit may be traced from line L, by conductor 70 throughsaid windin TR, conductors 71 and 72 to segment 7 30 the master switch,contactor 55 to said contact 1, by conductor 7 4 to the first contact 1of the position switch, through bridlging contactor 75 to se%nent 76,and by con uctor 77 to line L. nergization of winding TR effects closureof contacts TR of the relay, after a given time delay occasioned byemployment of the dashpot TR (Fig. 1). Contacts TR when closed providefor completion of the energizing circuits of switches M, F and F Theenergizing circuit of switch M may be traced from line L, by conductor78 throu h said contacts TR conductor 79 throug said winding toconductor 72 and segment 73, and thence through contactor 55 to line Las just traced. The energizin circuit for switches F, F may be tracedfrom line L by conductor 78 through contacts TR and conductor 79 inparallel through the windings of said switches to segment 80, and thencethrou h contactor 55 to line L as previously trace Closure of switchesM, F and F completes an energizing circuit for motor M to effectoperation thereof in one direction, as will be obvious; series relaysLR, LR, having lockout windings, being ada ted to control the startingresistances R 2 in a well known manner. Closure of switch F likewiseefi'ects closure of its auxiliary contacts F thereby completing acircuit for the run lamp indicated at the lower left-hand side of Fig.2, said circuit being obvious. Closure of switch F effects closure ofits auxiliary contacts F" whereby upon closure of the switch FH, afterone-sixth of a revolu- -tion of the hopper F, an energizing circuit isductor 84 through contacts FH, and by con- 1 ductors 85 and 86 to lineL. Upon opening of contacts PS protective resistance r is included incircuit with winding PS, as will be obvious. Upon operation ofratcheting mechanism PS, the bridging contactor 75 of the positionswitch is moved one space, into engagement with button 2 of the 60section of the position switch. Upon movement of contactor 75 out ofengagement with button 1 of said section in the manner just describedthe aforedescribed energizing circuits of switches M, F and F areinterrupted, thereby interrupting the motor circuit connections andreleasin brake SB to effect stopping of the motor afie'r rotation of thedistributing disk through an angle of 60. As aforedescribed suitablemeans is providedfor discharging the material from the bell B prior todumping of the next bucket load t ereonto.

It will be noted that upon movement of contactor 75 into engagement.with said but ton 2 an energizing circuit is provided for the 60indicating lamp; said circuit extend-' ing from line L through saidlamp, by conductor 87 to segment ,88, thence through contactor 75 tosegment 76 and by conductor 77 to line L.

Upon arrival of the next skip bucket at the furnace top winding MS isagain enregized,

bridging contactor 55 as aforedescribed,

thence to said button 2, by conductor 89 to button 2 of the 60 sectionof the position switch, through contacton 75 to segment 76 and thence byconductor 77 to line L. Motor M is therefore again operated, and uponrotation of the distributing hopper through an angle of 60 switch FH isa 1n closed. The

resulting energization of winding PS effects ratcheting of contactor 75through one s ace to engage button 3 of the 60 section 0 the positionswitch. It will be noted that movement of said contactor out ofengagement with button 2 of said section effects interrlliftion of theenergizing circuits of switches F and F and stopping of the motor in themanner aforedescnbed.

Motor M is intermittently operated in the manner aforedescribed to caeach skip bucket load to a point 60 removed from that at which it isreceived, until five loads have been so received and discharged;whereupon contactor 75 of the position switch is moved one space intoengagement with button 1 in the 120 section of said switch. It thereforeresults that upon the next 0 eration of the master switch ratcheting mecanism MS, the energizing circuits of switches M, F and F are completedand will be maintained pending two complete revolutions of switch FH, Ywhereby the distributing hopper 1s rotated loads have been carried toand discharged at through an angle of 120 prior to sto ping of themotor. The next four skip loa s are each likewise carried by the hopperF and bell B to a point 120 removed from the point at which they arereceived from the skil s) buckets. In the foregoing manner five loa havebeen received by and discharged from the hopper in the 0 orstationaryposition of the latter; five loads have been carried to and dischargedat a oint removed from the point at which t ey were received; and five apoint 120 from the point at which they were received.

' When the fifth load is carried to the 120 position the contactor 7 5of the position the position switch. Moreover, upon arrival anddischarge of the next load into hopper F the master switch ratchetingdevice is operated in the manner aforedescribed to effect movement ofcontactor 55 out of engagement with segment 80 and into engagement withsegment 92 and button 1 of t e 180 section of the master switch.This'again' completes an energizing circuit for relay TR, which uponclosure completes an energizing circuit for main switch M in the manneraforedescribed. However, under these conditions an energizing circuitwill be completed for the windings of switches B B, which results inoperation of motor M in. a reverse direction. It will be noted that therovision of three buttons in each grou in't e 180 section of theposition switc will necessitate three operations of the ratchetinmechanism PS prior to interruption of t e motor circuit connections, andhence the distributing hopper will be required to rotate through anangle of 180 prior to lowering-of bell B. While I have shown means forreversing-the motorto effect movement of the distributing disk to the180 position, it will be obvious that by extending the segment 80 tocover the 180 section of the master switch such movement could beeffected through operation of the motor in the first mentioneddirection.

It will be noted that upon closure of the auxiliary contacts B of switchB an alternative energizing circuit is provided for the 'fullydistributed without re uiring movement of the distributing dis throughan angle greater than 180. Therefore after the fifth load has beencarried to the 180 position by the hopper, contactor 75 will have movedinto engagement with segment 93 and button 1 in the 240 section of theposition switch, and upon arrival of the next skip 'run lamp, saidcircuit being obvious.

bucket the master-switch ratcheting mecha-' nism will effect movement ofcontactor 55 into engagement with button 1 in the 240- section of themaster switch; The aforedescribed reverse circuit connections for motorM are thus completed, and the hopper is rotated in a reverse directionthrough an angle of as'measured by operationof the limit switch BHthrough two complete cycles.

The load is therefore carried by the ho per to the point to which itwould have een carried if the hopper had been rotated in a forwarddirection through an angle of 240, whereas the time requiredfor suchreverse 1,so1,eoa

operation is only one-half as long. Five i be moved into engagement withsegment 94 and button 1 in the 300 section of the position switch, andupon discharge of the next skip load into the distributing hoppercontactor 55 will be moved into engagement .same, a

respect to each other means adapts closure of said switches apredetermined numwith button 1 in the 300 section of the master switch.The reverse circuit connections for motor M are thus again completed,and the hopper is rotated in a reverse direction through an angle of 60as measured by one complete rotation of switch BH. The

hopper is thus moved toa position corresponding to rotation of thehopper in a forward direction through an angle. of 300, while requiringbut one-fifth as much time for the operation. After five skip loads havebeen carried by the hopper to the 300 point by five operations thereofthrough an an le of 60 in said reverse direction, contactor 5 will bemoved to the initial position shown, wherein it engages contact 1 of thefirst section on the position switch, so that u on arrival of the nextskip bucket at the urnace top contactor will be moved into enga ementwith button 1 in the 0 section of t e master switch. The complete cyo'leaforedescribcd'will then-be repeated to effect continuation of thefurnace charging operation.

As aforeindicated the contactor 75 by sequential engagement withsegments 88, 90, 91, 93 and 94 of the position switch provides forcompletion of the energizing circuits of the 120, 180, 240 and 300lamps, thereby visually indicating the condition or prtv gfim of thefurnace charging operation.

'le I haveillustrated a controller adapt-V ed to provide for dischargeof five loads at each 0 six difierent angular positions of the hopper,it will be apparent to those skilled in the art that the invention isually applicable for a ch cycle inclu ing disc er of any desire numberof loads at any position or any number of positions.

What I claim as new and desire to secure by Letters Patent is:

1. In combination, a device to be rotatably driven, a reversible motorfor drivin the pluraliti of normally open switches to be clomd anreopened alternatel with upon her of times to effect completion of thecir cuit of said motor for operation thereof in one direction, saidmeans comprising aswitch having a plurality of groups of contacts and acontactor to be alternately engaged with d 'fromthe contacts of thereps, and another switch having a plurality of ups of contacts and acontactor to be a ternately engaged with and disengaged from thecontacts of said groups respectively, the contacts of said lastmentioned groups being of different lengths and the contactor associatedtherewith bein operable in accordance with the degree 0% rotation ofsaid device whereby said motor is operated automatically for difi'erentperiods during a given cycle, and means adapted upon a given num er ofoperations of certain of said contactors to rovide circuit connectionsfor operation 0 said motor in the opposite direction.

2. In combination, a rotatable device, a reversible electric drivingmotor therefor, control means for said motor, said means actingautomatically to effect a predetermined number ofintermittent operationsof said rotatable device in one direction throughout a given range andfor thereafter efiectmg a corresponding number of intermittentoperations of said device in the same direction throughout a difierentrange, and associated means operable automatically to selectively efiectintermittent operations of said device in the reverse directionth'roughout different ranges, the range of operation in each instancebeing not in excess of substantially 180 degrees.

3. In combination, a rotatable device, a reversible electric drivingmotor therefor,

control means for said motor, said means acting automatically to effecta predeter mined number of intermittent o erations of said rotatabledevice in one direction throughout a given range and for thereaftereffecting a corresponding number of intermittent operations of saiddevice in the same direction throughout a different range, andassociated means operable automatically to selectively effect a corresnding number of intermittent operations 0 said device in the reversedirection throughout each of a number'of different ranges, the rangeofoperation in each instance being not in excess of substantially one-halfof one complete rotation of said device.

4. In combination, a rotatable device a reversible electric drivingmotor therefor, control means for said motor, said means actingautomatically to effect a predetermined number of intermittentoperations of said rotatable device in one direction thro hout a givenrange and for thereafter effecting a correspondin number of intermittentoperations of sai deviceinthe same direction throughout a differentrange, and associated means operable automatically to selectively efiecta corresponding number of intermittentoperations of said device in thereverse direction throughout each of a number of difiere'nt ran therange of operation in each instance tially one-half of one completerotation of g not in excess of substan-- said device, the values of thelongerran cs directions eing o of operation in each direction beingmultip es of the values of the shortest range of operation in therespective directions.

. 5. In combination, a rotatable device reversible electricdriving motortheref control-means for said motor, said means act- I ing automaticallyto eifect a predetermined number of intermittent operations ofsaidrotatable device in one direction throu bout a given range and forthereafter effecting a correspondin number of intermittent opera tionsof sai device in the same direction throughout a different range, andassociated means operable automatically to selectively eifect acorresponding number of intermittent operations of said device in thereverse direct1on throughout each of a number of different ranges, therange of operation in each instance being not in excess of substantiallyone-half of one complete rotation of said device, the values of thelonger rarilges of operation in each direction being 111 of the valuesof the shortest range of operation in the respective directions andcertain of the ran es of OFQI'fltiOD in the respective equal values.

6. In a controller, in combination, a re-. versible electric motor, apair of circuitcontrolling elements each to be operated progressivelyand unidirectionally in-a series of steps,

one of said elements being adapted upon a predetermined plurality ofprogressive operations thereof to effect completion of the circuitconnections of said motor for operation thereof in one direction, theother of said elements being thereafter adapted upon a predeterminednumber of progressive operations thereof to effect interruption of themotor circuit connections pending subsequent operation of said firstmentioned element, sai elements being operable automatically and certainof the same having means adapted upon a predetermined plurality ofprogressive operations thereof to thereafter successively providereverse circuit connections for said motor. I

- 7. In acontroller, in combination, a'reversible electric motor, apair-of separately operable switches, associated means for eifectingintermittent progressive operation of one of said switches, said switchbeing adapted upon a predetermined plurality of progressive operationsthereof to complete the circuit connections of said motor for operationthereof in one direction, means opera 1e by said motor to effectprogressive o eration of the other of said switches to there y interruptthe motor circuit connections after a predetermined period of operationof said motor, said first mentioned switch bein thereafter operable toagain complete said st mentioned circuit for the motor, and meansassociated with said first mentioned switch and adapted upon apredetermined plurality of progressive tiples for a 1n sai 0 rationsof-the latter to thereafter successively provide circuit connections foroperation of said motor in the. reverse direction.

8. In a controller for electric motors,

ini combination electroresponsive switches.

adapted when closedselectively to provide forward or reverse circuitconnections for the motor, means for controlling said electroresponsiveswitches, said means comprising a pair of normally open limit switchestobe closed alternately and a plurality of automatically operable switchesassociated therewith, said last mentioned switches being operablesequentially and unidirectionally in a step-by-step manner to providefor repeated completion of the motor circuit connections plurality ofcontacts and a contactor mova le unidirectionally to engage anddisengage said contacts in a step-by-step manner, means adapted upon apredetermined plurality of progressive operations of one of saidcontactors to complete the energizing circuit of certain of saidelectroresponsive switches whereby the motor is operated in onedirection, means adapted upon operation of the motor redetermined numberof revolutions other of said contactors where y said energizing circuitis interrupted, said first mentioned and second mentioned contactorsbeing operable sequentially and unidirectionally to alternately completeand interrupt said energlzmg circuit, and means adapted uponpredetermined glurality of pro ssive operations of sai first mentionecontactor to thereafter provide for completion of the energizing circuitofother of said electrorespon-l sive switches whereby circuitconnections are direction to effect o eration of the provided forsuccessive operation of said motor in the reverse direction.

10. In combination, a device to be rotatably driven, a reversible motorfor driving the same, a plurality of normally open limit switches to beclosed and reopened alternately means adapted upon closure of saidswitches a multiphcit of times to effect completion of the circuit 0said motor for operation thereof one direction, said means comprisin asw tch having a plurality of contacts and a unidirectionally movablecontactor to be engaged therewith-and disengaged therefrom progressivelyin response to operation of said limit switches, another switch having aplurality of contacts and a unidirectionally movable contactor to beengaged therewith and disengaged therefrom progressively in response tothe degree of rotation of said device to thereby rovide for interruptionof the motor circult connections pending reclosure of one of said limitswitches, and means associated with said contactors and adapted upon apredetermined plurality of progressive operations thereof to thereaftersuccessively provide circuit connections for operation of said motor inthe reverse direction.

In witness whereof, I have hereunto subscribed my name.

PAISLEY B. HARWOOD.

